This proposal aims to uncover the biochemical processes that regulate the formation and breakage of specific neuronal connections. For chemical synapses these phenomena are well understood, however little is known about the mechanism(s) involved in electrical synapses. We propose to address whether protein synthesis and/or cytoskeletal components are involved in these neuronal plastic events of electrical synapses. The buccal ganglia of Helisoma, with its identifiable neurons, is known to be an excellent model in which to study neuronal plasticity of electrotonic connections. Extensive work has shown that these large adult neurons can be induced to sprout and regenerate old and new connectivity patterns. Such connections arise by forming many synapses, with subsequent breaking of "inappropriate" synapses upon formation of a priority connection. While much is known about the phenomenology of these events; little is known concerning the biochemical and molecular mechanisms involved. Our study will investigate the molecular mechanisms underlying the formation of these novel connections and the specific elimination of those connections of lower priority. We are particularly interested in addressing the question of whether either of these processes is dependent upon ongoing protein synthesis or is regulated by the cytoskeletal architecture of the cell. Using electrophysiological and fluorescence microscopy techniques, we will monitor the formation and elimination of specific electrical synapses both in the normal ganglionic environment and in isolated cell culture.